Cyanamides and nitriles can react with alkaline hydrogen peroxide to form a peroxyimidic intermediate, which is a powerful oxidant. Thus, for example, Payne, Tetrahedron, 18, pp. 763-765 (1962) describes the reaction of benzonitrile and hydrogen peroxide to give an extremely reactive intermediate termed peroxybenzimidic acid. This intermediate is too reactive to be isolated, and actually will oxidize hydrogen peroxide itself to oxygen. Sawaki, Bull. Chem. Soc. Jpn., 54, pp. 793-799 (1981) summarized the reaction described by Payne, supra and also studied the effect of certain substituted benzonitriles (p-MeOPhCN, p-MePhCN, m-MePhCN, o-MePhCN, p-ClPhCN, and p-O.sub.2 NPhCN.
U.S. Pat. No. 4,756,845, issued Jul. 12, 1988, inventors Sugawara et al., discloses peroxide activators such as alkyl or alkoxy substituted dicyanobenzenes.
European patent application 91201170.7, published Nov. 27, 1991, inventor Oakes discloses peroxyacid bleach precursors such as can be prepared from an aromatic aldehyde or ketone by reaction with sodium cyanide and a dialkyl amine.
However, problems with the previously known cyanamide and nitriles have included limited stability, poor bleaching effectiveness, or a small amount of active oxidizing intermediate being formed.